[Is "tobacco harm reduction" possible? Other countries' experiences and perspectives, and how they could inform tobacco control in Japan]

　"Tobacco harm reduction" is defined as a method to minimize harm and risk of death and disease without eliminating tobacco and nicotine use. In Japan, where heated tobacco products (HTPs) are prevalent, the tobacco industry is progressively endorsing the concept of "tobacco harm reduction." Therefore, stakeholders in tobacco control must urgently share perspectives and experiences surrounding this issue.　This discussion paper aimed to propose four requirements for effectively implementing "tobacco harm reduction" as a public health measure: (1) disease risk reduction, (2) cigarette smoking cessation, (3) no additional public health concerns, and (4) regulatory authorities held by health agencies, and compile information on them regarding nicotine-containing electronic cigarettes (e-cigarettes) and HTPs. Another aim was to summarize policies related to "tobacco harm reduction" adopted by an international organization (World Health Organization (WHO) and health authorities in foreign countries (the United States of America (USA), the United Kingdom (UK), Australia, Italy, and the Republic of Korea) to explore the implications of these requirements on Japan's approach. Regarding the first three requirements, scientific evidence indicated that e-cigarettes offers some level of risk reduction and can assist with cigarette smoking cessation. The potential uptake of e-cigarettes among youth and their possibility to serve as a gateway to combusted cigarette use is a concern, though a definitive causal link is yet to be established between the uptake of e-cigarette in youth and the subsequent use of different tobacco products. There is insufficient scientific evidence for any of the three requirements for HTPs. Regarding the official policies, WHO took the position that the same regulations should be applied to all tobacco products. Only the UK and USA officially established a health system based on the concept of "tobacco harm reduction"; even in Italy and the Republic of Korea, where HTPs are relatively widespread, health authorities denied any risk reduction by introducing HTPs. The UK officially adopted a smoking cessation policy with e-cigarettes. The USA established a modified risk tobacco product system under federal legislation enacted in 2009, whereas of June 2023, no HTP or e-cigarettes were recognized as explicitly reducing health risk. Regarding the fourth requirement, the UK and USA institutionalized "tobacco harm reduction" under health authorities' regulation independent of the tobacco industry. The introduction of a tobacco harm reduction policy in Japan should be considered only in line with health authorities' regulation and implementation of comprehensive tobacco control measures independent of the tobacco industry.

Cannabidiol as a potential cessation therapeutic: Effects on intravenous nicotine self-administration and withdrawal symptoms in mice

Cigarette smoking remains a leading cause of preventable disease and death worldwide. Due to the devastating negative health effects of smoking, many users attempt to quit, but few are successful in the long-term. Thus, there is a critical need for novel therapeutic approaches. In these investigations, we sought to examine whether cannabidiol (CBD) has the potential to be repurposed as a nicotine cessation therapeutic. In the first study, male and female mice were trained to respond for intravenous nicotine infusions at either a low or moderate nicotine dose and then were pretreated with CBD prior to their drug-taking session. We found that CBD produced a significant decrease in the number of nicotine rewards earned, and this effect was evidenced across CBD doses and with both the low and moderate levels of nicotine intake. These effects on drug intake were not due to general motor-related effects, since mice self-administering food pellets did not alter their behavior with CBD administration. The potential effects of CBD in mitigating nicotine withdrawal symptoms were then investigated. We found that CBD attenuated the somatic signs of nicotine withdrawal and prevented nicotine's hyperalgesia-inducing effects. Taken together, these results demonstrate that modulation of cannabinoid signaling may be a viable therapeutic option as a smoking cessation aid.

Genetic regulation and manipulation of nicotine biosynthesis in tobacco: strategies to eliminate addictive alkaloids

Tobacco (Nicotiana tabacum L.) is a widely cultivated crop of the genus Nicotiana. Due to the highly addictive nature of tobacco products, tobacco smoking remains the leading cause of preventable death and disease. There is therefore a critical need to develop tobacco varieties with reduced or non-addictive nicotine levels. Nicotine and related pyridine alkaloids biosynthesized in the roots of tobacco plants are transported to the leaves, where they are stored in vacuoles as a defense against predators. Jasmonate, a defense-related plant hormone, plays a crucial signaling role in activating transcriptional regulators that coordinate the expression of downstream metabolic and transport genes involved in nicotine production. In recent years, substantial progress has been made in molecular and genomics research, revealing many metabolic and regulatory genes involved in nicotine biosynthesis. These advances have enabled us to develop tobacco plants with low or ultra-low nicotine levels through various methodologies, such as mutational breeding, genetic engineering, and genome editing. We review the recent progress on genetic manipulation of nicotine production in tobacco, which serves as an excellent example of plant metabolic engineering with profound social implications.

Alpha5 nicotine acetylcholine receptor subunit promotes intrahepatic cholangiocarcinoma metastasis

Neurotransmitter-initiated signaling pathway were reported to play an important role in regulating the malignant phenotype of tumor cells. Cancer cells could exhibit a "neural addiction" property and build up local nerve networks to achieve an enhanced neurotransmitter-initiated signaling through nerve growth factor-mediated axonogenesis. Targeting the dysregulated nervous systems might represent a novel strategy for cancer treatment. However, whether intrahepatic cholangiocarcinoma (ICC) could build its own nerve networks and the role of neurotransmitters in the progression ICC remains largely unknown. Immunofluorescence staining and Enzyme-linked immunosorbent assay suggested that ICC cells and the infiltrated nerves could generate a tumor microenvironment rich in acetylcholine that promotes ICC metastasis by inducing epithelial-mesenchymal transition (EMT). Acetylcholine promoted ICC metastasis through interacting with its receptor, alpha 5 nicotine acetylcholine receptor subunits (CHRNA5). Furthermore, acetylcholine/CHRNA5 axis activated GSK3β/β-catenin signaling pathway partially through the influx of Ca2+-mediated activation of Ca/calmodulin-dependent protein kinases (CAMKII). In addition, acetylcholine signaling activation also expanded nerve infiltration through increasing the expression of Brain-Derived Neurotrophic Factor (BDNF), which formed a feedforward acetylcholine-BDNF axis to promote ICC progression. KN93, a small-molecule inhibitor of CAMKII, significantly inhibited the migration and enhanced the sensitivity to gemcitabine of ICC cells. Above all, Acetylcholine/CHRNA5 axis increased the expression of β-catenin to promote the metastasis and resistance to gemcitabine of ICC via CAMKII/GSK3β signaling, and the CAMKII inhibitor KN93 may be an effective therapeutic strategy for combating ICC metastasis.

Epigenome-wide association study of total nicotine equivalents in multiethnic current smokers from three prospective cohorts

The impact of tobacco exposure on health varies by race and ethnicity and is closely tied to internal nicotine dose, a marker of carcinogen uptake. DNA methylation is strongly responsive to smoking status and may mediate health effects, but study of associations with internal dose is limited. We performed a blood leukocyte epigenome-wide association study (EWAS) of urinary total nicotine equivalents (TNEs; a measure of nicotine uptake) and DNA methylation measured using the MethylationEPIC v1.0 BeadChip (EPIC) in six racial and ethnic groups across three cohort studies. In the Multiethnic Cohort Study (discovery, n = 1994), TNEs were associated with differential methylation at 408 CpG sites across >250 genomic regions (p < 9 × 10-8). The top significant sites were annotated to AHRR, F2RL3, RARA, GPR15, PRSS23, and 2q37.1, all of which had decreasing methylation with increasing TNEs. We identified 45 novel CpG sites, of which 42 were unique to the EPIC array and eight annotated to genes not previously linked with smoking-related DNA methylation. The most significant signal in a novel gene was cg03748458 in MIR383;SGCZ. Fifty-one of the 408 discovery sites were validated in the Singapore Chinese Health Study (n = 340) and the Southern Community Cohort Study (n = 394) (Bonferroni corrected p < 1.23 × 10-4). Significant heterogeneity by race and ethnicity was detected for CpG sites in MYO1G and CYTH1. Furthermore, TNEs significantly mediated the association between cigarettes per day and DNA methylation at 15 sites (average 22.5%-44.3% proportion mediated). Our multiethnic study highlights the transethnic and ethnic-specific methylation associations with internal nicotine dose, a strong predictor of smoking-related morbidities.

The prevalence and sociodemographic determinants of tobacco and nicotine use among students in healthcare disciplines in Saudi Arabian universities: a cross-sectional survey

Background

Tobacco smoking is one of the most significant health-related problems worldwide. However, the prevalence and sociodemographic determinants of tobacco and nicotine use among students on healthcare courses in Saudi Arabia are limited.

Methods

This cross-sectional study used a questionnaire that was distributed via SurveyMonkey between November 2022 and June 2023 to all student universities offering healthcare courses. Data are presented as frequency and percentages. The associated sociodemographic factors with current tobacco and nicotine use were subjected to logistic regression.

Results

Overall, 5,012, of whom 3,872 (77.25%) were males, responded to the online survey. The prevalence of current tobacco and nicotine use was 3,553 (71%). The majority of users used electronic nicotine delivery systems (1,622: 32.36%). The current use of cigarettes (AOR: 1.75 (1.42 to 2.15)), e-cigarettes (AOR: 1.17 (1.01 to 1.37)), and smokeless tobacco substances (AOR: 1.35 (1.02 to 1.90)) were more pronounced among males compared to female students. However, the current use of a hookah was less among males (AOR: 0.74 (95% CI: 61 to 0.91)). Smoking cigarettes was practiced less among students living in other regions compared to the Central Region. However, smokeless tobacco substances seem to be more prevalent in the Western, Southern, and Northern Regions, (AOR: 1.57 (95% CI: 1.09 to 2.26)), (AOR: 1.43 (95% CI: 1.04 to 1.95)), and (AOR: 1.57 (95% CI: 1.09 to 2.26)), respectively.

Conclusion

Smoking is prevalent among students in the healthcare disciplines, with electronic nicotine delivery systems being the most used product. Several sociodemographic factors were associated with higher tobacco or nicotine use.

Mutation in shoot-to-root mobile transcription factor, ELONGATED HYPOCOTYL 5, leads to low nicotine levels in tobacco

Tobacco remains one of the most commercially important crops due to the parasympathomimetic alkaloid nicotine used in cigarettes. Most genes involved in nicotine biosynthesis are expressed in root tissues; however, their light-dependent regulation has not been studied. Here, we identified the ELONGATED HYPOCOTYL 5 homolog, NtHY5, from Nicotiana tabacum and demonstrated that NtHY5 could complement the Arabidopsis thaliana hy5 mutant at molecular, morphological and biochemical levels. We report the development of CRISPR/Cas9-based knockout mutant plants of tobacco, NtHY5CR, and show down-regulation of the nicotine and phenylpropanoid pathway genes leading to a significant reduction in nicotine and flavonol content, whereas NtHY5 overexpression (NtHY5OX) plants show the opposite effect. Grafting experiments using wild-type, NtHY5CR, and NtHY5OX indicated that NtHY5 moves from shoot-to-root to regulate nicotine biosynthesis in the root tissue. Shoot HY5, directly or through enhancing expression of the root HY5, promotes nicotine biosynthesis by binding to light-responsive G-boxes present in the NtPMT, NtQPT and NtODC promoters. We conclude that the mobility of HY5 from shoot-to-root regulates light-dependent nicotine biosynthesis. The CRISPR/Cas9-based mutants developed, in this study; with low nicotine accumulation in leaves could help people to overcome their nicotine addiction and the risk of death.

National Trends in Sales and Price for Commercial Tobacco and Nicotine Products, 2018-2022

This cross-sectional study explores recent trends in sales and price of tobacco and nicotine products in the US.

Electronic hookah (waterpipe) vaping reduces vascular endothelial function: the role of nicotine

Vaping has risen substantially in recent years, particularly among young adults. Electronic (e-) hookahs are a newer category of vaping devices touted as safer tobacco alternatives. Although e-hookah vaping acutely reduces endothelial function, the role of nicotine and the mechanisms by which it may impair endothelial function remain understudied. In a randomized crossover study, we investigated the acute effects of vaping e-hookah, with and without nicotine, as compared with sham on endothelial function assessed by brachial artery flow-mediated dilation (FMD), among 18 overtly healthy young adults. To determine the role of changes in circulating factors in plasma on endothelial cell function, human umbilical vein endothelial cells (HUVECs) were cultured with participants' plasma, and acetylcholine-stimulated nitric oxide (NO) production and basal reactive oxygen species (ROS) bioactivity were assessed. Plasma nicotine was measured before and after the sessions. E-hookah vaping with nicotine, which acutely increased heart rate (HR) by 8 ± 3 beats/min and mean arterial pressure (MAP) by 7 ± 2 mmHg (means ± SE; P < 0.05), decreased endothelial-dependent FMD by 1.57 ± 0.19%Δ (P = 0.001), indicating impairment in endothelial function. Vaping e-hookah without nicotine, which mildly increased hemodynamics (HR, 2 ± 2 beats/min and MAP 1 ± 1 mmHg; P = ns), did not significantly impair endothelial function. No changes were observed after sham vaping. HUVECs cultured with participants' plasma after versus before e-hookah vaping with nicotine, but not without nicotine or sham vaping, exhibited reductions in endothelial cell NO bioavailability and increases in ROS bioactivity (P < 0.05). Plasma nicotine concentrations increased after vaping e-hookah with nicotine (6.7 ± 1.8 ng/mL; P = 0.002), whereas no changes were observed after vaping e-hookah without nicotine or sham (P = ns). Acute e-hookah vaping induces endothelial dysfunction by impairing NO bioavailability associated with increased ROS production, and these effects are attributable to nicotine, not to nonnicotine constituents, present in the flavored e-liquid.NEW & NOTEWORTHY Despite safety claims heavily advertised by the hookah tobacco industry, acute e-hookah vaping induces in vivo endothelial dysfunction by impairing ex vivo NO bioavailability associated with increased ROS production. These effects are attributable to nicotine, not to nonnicotine constituents, present in the flavored e-liquid.

Mifepristone decreases nicotine intake in dependent and non-dependent adult rats

BACKGROUND

Addiction to tobacco and nicotine products has adverse health effects and afflicts more than a billion people worldwide. Therefore, there is an urgent need for new treatments to reduce tobacco and nicotine use. Glucocorticoid receptor blockade shows promise as a novel treatment for drug abuse and stress-related disorders.

AIM

These studies aim to investigate whether glucocorticoid receptor blockade with mifepristone diminishes the reinforcing properties of nicotine in rats with intermittent or daily long access to nicotine.

METHODS

The rats self-administered 0.06 mg/kg/inf of nicotine for 6 h per day, with either intermittent or daily access for 4 weeks before treatment with mifepristone. Daily nicotine self-administration models regular smoking, while intermittent nicotine self-administration models occasional smoking. To determine whether the rats were dependent, they were treated with the nicotinic acetylcholine receptor antagonist mecamylamine, and somatic signs were recorded.

RESULTS

The rats with intermittent access to nicotine had a higher level of nicotine intake per session than those with daily access but only the rats with daily access to nicotine showed signs of physical dependence. Furthermore, mecamylamine increased nicotine intake during the first hour of access in rats with daily access but not in those with intermittent access. Mifepristone decreased total nicotine intake in rats with intermittent and daily access to nicotine. Moreover, mifepristone decreased the distance traveled and rearing in the open field test and operant responding for food pellets.

CONCLUSION

These findings indicate that mifepristone decreases nicotine intake but this effect may be partially attributed to the sedative effects of mifepristone.

Adolescent Tobacco/Nicotine Use and the Potential Role of Contingency Management-based Interventions

ABSTRACT

The high prevalence of tobacco/nicotine use among youth, including e-cigarettes, is a public health problem in the United States. Early exposure leads to an increased risk of dependence and health consequences in adulthood. We reviewed the literature on current treatment approaches for nicotine/tobacco use in adolescents/young adults and highlighted underexplored areas of treatment research. There are no current Food and Drug Administration-approved medications for treatment of nicotine/tobacco use disorders in adolescents. However, in research settings and on a case-to-case basis, clinical practice medications (including nicotine replacement therapy, bupropion, and varenicline) have been prescribed to this population with consideration of risk-benefit analysis when behavioral treatments are not sufficient to address dependence. Among the nonpharmacological interventions, there is evidence to support the potential for expanded use of contingency management in youth. Neural differences predisposing adolescents to substance use, along with higher attentiveness to value of options in decision making (flexible reward system) may enhance the effectiveness of reward-based approaches for treatment of substance use disorders in this population. The overall high rates of nonresponders across psychosocial and pharmacological treatments highlight the importance of considering novel strategies to improve existing interventions. We suggest that future research be done that considers unique characteristics of today's adolescents, such as high social activism and engagement with digital rewards to tailor contingency management for this age group and assess its effectiveness. Adolescents could potentially benefit from rewards administered through digital media (eg, video games, computer-based apps, and social media influencers).

Evaluating the effects of nicotine concentration on the appeal and nicotine delivery of oral nicotine pouches among rural and Appalachian adults who smoke cigarettes: A randomized cross-over study

BACKGROUND AND AIMS

Oral nicotine pouches (ONPs) probably offer reduced harm compared with cigarettes, but independent data concerning their misuse liability are lacking. We compared nicotine delivery and craving relief from ONPs with different nicotine concentrations to cigarettes.

DESIGN

This was a single-blind, three-visit (≥ 48-hour washout), randomized-cross-over study. Participants were encouraged to complete all study visits in less than 1 month.

SETTING

The study took place in Rural/Appalachian Ohio.

PARTICIPANTS

Participants comprised 30 adults who smoke cigarettes. Participants (meanage  = 34.5) were 60% men and 90% White.

INTERVENTION

Participants who were ≥ 12-hour tobacco-abstinent used: (1) a 3-mg nicotine concentration ONP, (2) a 6-mg nicotine concentration ONP and (3) usual brand cigarette in separate visits. ONPs (wintergreen Zyn) were used for 30 minutes; cigarettes were puffed every 30 sec for 5 minutes.

MEASUREMENTS

Plasma nicotine and self-reported craving were assessed at t = 0, 5, 15, 30, 60 and 90 minutes. The primary outcome was plasma nicotine concentration at t = 30 minutes. A secondary outcome was craving relief at t = 5 minutes.

FINDINGS

At t = 30, mean [95% confidence interval (CI)] plasma nicotine was 9.5 ng/ml (95% CI = 7.1, 11.9 ng/ml) for the 3 mg nicotine ONP, 17.5 ng/ml (95% CI = 13.7, 21.3) for the 6 mg nicotine ONP and 11.4 ng/ml (95% CI = 9.2, 13.6 ng/ml) for the cigarette. Mean plasma nicotine at t = 30 minutes differed between the 3- and 6-mg nicotine ONPs (P = 0.001) and between the 6-mg nicotine ONP and cigarette (P = 0.002). Mean (95% CI) craving at t = 5 minutes was lower for the cigarette (mean = 1.00, 95% CI = 0.61, 1.39) than either the 3 mg (mean = 2.25, 95% CI = 1.68, 2.82; P < 0.0001) or 6 mg nicotine (mean = 2.19, 95% CI = 1.60, 2.79; P < 0.0001) ONP.

CONCLUSIONS

Among adult smokers, using 6-mg nicotine concentration oral nicotine pouches (ONPs) was associated with greater plasma nicotine delivery at 30 minutes than 3-mg ONPs or cigarettes, but neither ONP relieved craving symptoms at 5 minutes as strongly as a cigarette. Accelerating the speed of nicotine delivery in ONPs might increase their misuse liability relative to cigarettes.

Designing and preparing supramolecular encapsulation systems based on fraxetin and cyclodextrins for highly selective detection of nicotine

Herein, a series of water-soluble supramolecular inclusion complexes (ICs) probes were prepared using cyclodextrins (CDs) and fraxetin (FRA) to detect nicotine (NT) with high selectivity in vitro and in vivo. The FRA/CD ICs prepared through the saturated solution method exhibited excellent water solubility, stability, and biocompatibility. A clear host-guest inclusion model was provided by the theoretical calculations. The investigation revealed that NT was able to enter into the cavities of FRA/β-CD IC and FRA/γ-CD IC, and further formed charge transfer complexes with FRA in the CD cavities, resulting in a rapid and highly selective fluorescence-enhanced response with the lowest detection limits of 1.9 × 10-6 M and 9.7 × 10-7 M, and the linear response ranged from 0.02 to 0.3 mM and 0.01-0.05 mM, respectively. The IC probes showed good anti-interference performance to common interferents or different pH environments, with satisfactory reproducibility and repeatability of response to NT. Furthermore, the potentiality of the probes was confirmed through fluorescence imaging experiments using human lung cancer cells and the lung tissue of mice. This study offers a fresh perspective for detecting NT in environmental and biomedical analysis.

Why young adults use tobacco-free nicotine E-cigarettes: An analysis of qualitative data

BACKGROUND

Tobacco-free nicotine (TFN) is often marketed as being better tasting and healthier than tobacco-derived nicotine (TDN). Studies have yet to systematically characterize subjective experiences using TFN e-cigarettes. This qualitative study explored young adults' reasons for using TFN e-cigarettes and perceptions of differences between using TFN and TDN e-cigarettes.

METHOD

We conducted a national online Qualtrics survey of U.S. young adults aged 18-25 years in October 2021. Respondents who reported lifetime TFN e-cigarette use (n = 317, mean age: 20.8 (SD:2.2), 53.9 % female) provided write-in responses to open-ended questions assessing reasons for using TFN e-cigarettes and perceptions of differences between TFN and TDN e-cigarettes. Responses from participants were thematically analyzed by independent raters.

RESULTS

Reasons for using TFN e-cigarettes included product taste/flavor, health reasons (e.g. believing TFN was healthy), and product accessibility. Perceptions of differences between TFN and TDN e-cigarettes included differences in taste/ flavor and acute psychoactive and physical effects (e.g., nicotine buzz, throat hit), with TFN e-cigarettes being described as generally stronger and superior relative to TDN e-cigarettes.

CONCLUSION

These qualitative data suggest that taste and perceived health benefits are primary reasons that young adults try TFN e-cigarettes. Compared to TDN, young adults perceive TFN as better tasting with different psychoactive and less aversive effects. Determining if these perceived reasons for use and differences occur in blinded human experimental studies is a necessary next step to understanding TFN e-cigarette use. Additionally, understanding why young adults use TFN e-cigarettes is important in the development of prevention communication about these products.

Smoking Cessation Is Associated With Short-Term Improvement of Vascular Health in a Cohort of People Living With HIV in Rio de Janeiro, Brazil

Smoking is highly prevalent in people living with HIV/AIDS (PLHA), leading to detrimental effects in different tissues. We examined the effects of nicotine replacement therapy (NRT) on smoking cessation and vascular health. From December 2019 to October 2021, we prospectively enrolled PLHA who were actively smoking. The primary outcome was endothelial function measured by brachial artery flow-mediated dilatation (FMD). We evaluated the percent change in FMD compared to the baseline measure (Δ%FMD) to detect improvements among participants who quit smoking. To confirm the results, we used linear regression models to account for classical cardiovascular (CV) confounders. We included 117 participants with median age of 45.5 years (IQR= 36.4-54.8); 22 (20.4%) had hypertension, 9 (8.3%) had diabetes, almost half were smoking 20+ cigarettes/day (41.7%). After 12 weeks 30.76% participants quit smoking. Comparison of Δ%FMD change from baseline to week 12 showed that among participants adherent to therapy, there has been an increase in Δ%FMD when compared to those who relapsed (1.17% [0.29-2.98] vs -0.19% [-1.95-0.91], p<0.001). After adjustment for CV factors, multiple linear regression showed that Δ%FMD in participants who quit smoking presented a 2.54 mean increase in comparison to those who continued smoking (p=0.007). In conclusion, this study provides evidence that a strategy of NRT and counseling is modestly effective for smoking cessation in PLHA and improves vascular health in a short period of time. This reinforces the importance of the widespread anti-tobacco programs in HIV clinics and the expected impact lowering the incidence of future cardiovascular events.

A multicenter prospective randomized controlled trial investigating the effects of combustion-free nicotine alternatives on cardiovascular risk factors and metabolic parameters in individuals with type 2 diabetes who smoke: the DiaSmokeFree study protocol

Stopping smoking is crucial for public health and especially for individuals with diabetes. Combustion-free nicotine alternatives like e-cigarettes and heated tobacco products are increasingly being used as substitutes for conventional cigarettes, contributing to the decline in smoking prevalence. However, there is limited information about the long-term health impact of those products in patients with diabetes. This randomized controlled trial aims to investigate whether switching from conventional cigarettes to combustion-free nicotine alternatives will lead to a measurable improvement in cardiovascular risk factors and metabolic parameters over a period of 2 years in smokers with type 2 diabetes. The multicenter study will be conducted in seven sites across four countries. A total of 576 smokers with type 2 diabetes will be randomly assigned (1:2 ratio) to either standard of care with brief cessation advice (Control Arm) or combustion-free nicotine alternatives use (Intervention Arm). The primary end point is the change in the proportion of patients with metabolic syndrome between baseline and the 2-year follow-up. Additionally, the study will analyze the absolute change in the sum of the individual factors of metabolic syndrome at each study time point. Patient recruitment has started in September 2021 and enrollment is expected to be completed by December 2023. Results will be reported in 2026. This study may provide valuable insights into cardiovascular and metabolic health benefits or risks associated with using combustion-free nicotine alternatives for individuals with type 2 diabetes who are seeking alternatives to tobacco cigarette smoking. The study protocol, informed consent forms, and relevant documents were approved by seven ethical review boards. Study results will be disseminated through articles published in high-quality, peer-reviewed journals and presentations at conferences.

Rieske Iron-Sulfur Protein Mediates Pulmonary Hypertension Following Nicotine/Hypoxia Coexposure

The high mortality rate in patients with chronic obstructive pulmonary disease (COPD) may be due to pulmonary hypertension (PH). These diseases are highly associated with cigarette smoke and its key component nicotine. Here, we created a novel animal model of PH using coexposure to nicotine (or cigarette smoke) and hypoxia. This heretofore unreported model showed significant early-onset pulmonary vasoremodeling and PH. Using newly generated mice with complementary smooth muscle-specific Rieske iron-sulfur protein (RISP) gene knockout and overexpression, we demonstrate that RISP is critically involved in promoting pulmonary vasoremodeling and PH, which are implemented by oxidative ataxia telangiectasia-mutated-mediated DNA damage and NF-κB-dependent inflammation in a reciprocal positive mechanism. Together, our findings establish for the first time an animal model of hypoxia-induced early-onset PH in which mitochondrial RISP-dependent DNA damage and NF-κB inflammation play critical roles in vasoremodeling. Specific therapeutic targets for RISP and related oxidative stress-associated signaling pathways may create unique and effective treatments for PH, chronic obstructive pulmonary disease, and their complications.

Characterization of CYP2B6 and CYP2A6 Pharmacogenetic Variation in Sub-Saharan African Populations

Genetic variation in CYP2B6 and CYP2A6 is known to impact interindividual response to antiretrovirals, nicotine, and bupropion, among other drugs. However, the full catalogue of clinically relevant pharmacogenetic variants in these genes is yet to be established, especially across African populations. This study therefore aimed to characterize the star allele (haplotype) distribution in CYP2B6 and CYP2A6 across diverse and understudied sub-Saharan African (SSA) populations. We called star alleles from 961 high-depth full genomes using StellarPGx, Aldy, and PyPGx. In addition, we performed CYP2B6 and CYP2A6 star allele frequency comparisons between SSA and other global biogeographical groups represented in the new 1000 Genomes Project high-coverage dataset (n = 2,000). This study presents frequency information for star alleles in CYP2B6 (e.g., *6 and *18; frequency of 21-47% and 2-19%, respectively) and CYP2A6 (e.g., *4, *9, and *17; frequency of 0-6%, 3-10%, and 6-20%, respectively), and predicted phenotypes (for CYP2B6), across various African populations. In addition, 50 potentially novel African-ancestry star alleles were computationally predicted by StellarPGx in CYP2B6 and CYP2A6 combined. For each of these genes, over 4% of the study participants had predicted novel star alleles. Three novel star alleles in CYP2A6 (*54, *55, and *56) and CYP2B6 apiece, and several suballeles were further validated via targeted Single-Molecule Real-Time resequencing. Our findings are important for informing the design of comprehensive pharmacogenetic testing platforms, and are highly relevant for personalized medicine strategies, especially relating to antiretroviral medication and smoking cessation treatment in Africa and the African diaspora. More broadly, this study highlights the importance of sampling diverse African ethnolinguistic groups for accurate characterization of the pharmacogene variation landscape across the continent.

Effects of mint, menthol, and tobacco-flavored e-cigarettes on tobacco withdrawal symptoms in adults who smoke menthol cigarettes: A laboratory pilot study

BACKGROUND

Menthol cigarette smoking has remained stable or increased in certain groups, despite an overall decline in cigarette smoking rates in the U.S. Understanding whether e-cigarettes alter patterns of menthol cigarette use is critical to informing efforts for reducing the public health burden of menthol cigarette smoking. This 2019-2020 laboratory pilot study evaluated whether self-administration of mint-, menthol-, or tobacco-flavored e-cigarettes would differentially impact tobacco withdrawal symptoms in e-cigarette-naïve adults who smoke menthol cigarettes daily.

METHODS

Participants (N=17; 35.3% Female; mean age=51.8) attended three laboratory sessions after 16-hours of tobacco abstinence. Participants self-administered a study-provided JUUL e-cigarette (0.7mL with 5% nicotine by weight) at each session in which flavor was manipulated (mint vs. menthol vs. tobacco; order randomized). Participants completed pre- and post-e-cigarette administration self-report assessments on smoking urges, nicotine withdrawal, and positive and negative affect states. Multilevel linear regression models tested differences between the three flavor conditions for individual study outcomes.

RESULTS

Following overnight tobacco abstinence, vaping either a mint or menthol (vs. tobacco) flavored e-cigarette led to significantly greater reductions in smoking urges over time; menthol (vs. tobacco) flavored e-cigarettes also suppressed urges to smoke for pleasure. Notably, no differences in nicotine withdrawal, positive affect, or negative affect were observed.

CONCLUSIONS

In this laboratory pilot study, mint and menthol (vs. tobacco) flavored e-cigarettes provided some negative reinforcement effects via acute reductions in smoking urges during tobacco abstinence, yet only menthol flavored e-cigarettes demonstrated suppressive effects on smoking urges for pleasure in adults who smoke menthol cigarettes daily.

Associating CYP2A6 structural variants with ovarian and lung cancer risk in the UK Biobank: replication and extension

CYP2A6 is a polymorphic enzyme that inactivates nicotine; structural variants (SVs) include gene deletions and hybrids with the neighboring pseudogene CYP2A7. Two studies found that CYP2A7 deletions were associated with ovarian cancer risk. Using their methodology, we aimed to characterize CYP2A6 SVs (which may be misidentified by prediction software as CYP2A7 SVs), then assess CYP2A6 SV-associated risk for ovarian cancer, and extend analyses to lung cancer. An updated reference panel was created to impute CYP2A6 SVs from UK Biobank array data. Logistic regression models analyzed the association between CYP2A6 SVs and cancer risk, adjusting for covariates. Software-predicted CYP2A7 deletions were concordant with known CYP2A6 SVs. Deleterious CYP2A6 SVs were not associated with ovarian cancer (OR = 1.06; 95% CI: 0.80-1.37; p = 0.7) but did reduce the risk of lung cancer (OR = 0.44; 95% CI: 0.29-0.64; p < 0.0001), and a lung cancer subtype. Replication of known lung cancer associations indicates the validity of array-based SV analyses.

Evaluating the implementation of a prescription only regulatory model for nicotine vaping products: A qualitative study on the experiences and views of healthcare professionals

BACKGROUND

Deciding how to regulate nicotine vaping products (NVPs) is a challenge for many countries. Balanced regulation should consider the potential harms to young people from uptake of NVPs alongside the possible benefits of NVPs as a smoking cessation aid. One option is to make NVPs only available via medical prescription to adults who smoke. From October 2021, Australia adopted a unique model that allows prescription access to NVPs that meet a product standard without requiring the NVPs to be approved as therapeutic goods. This research explored the impact of this regulatory model on the smoking cessation practices of health professionals, and their views on the model.

METHODS

Semi-structured interviews were conducted with 39 Australian health professionals recruited from professional networks and social media. Health professionals were eligible if they provided smoking cessation advice as part of their role, and included medical practitioners (n = 9), pharmacists (n = 9), and other health professionals that provided smoking cessation counselling (n = 21). Interviews were mostly completed by phone and online teleconferencing software. Questions focused on smoking cessation practices, advice and information provided to patients about NVPs, views about the effectiveness of the model for supporting use of NVPs for smoking cessation and preventing youth uptake, and barriers and facilitators to prescribing and dispensing NVPs. Coding and analysis used a combination of inductive and deductive approaches.

RESULTS

Findings indicated a lack of consensus amongst the participants about NVPs as a cessation or harm reduction tool. Participants broadly agreed that the model has not been effective in improving quality control of NVPs, or in reducing youth access. Many participants eligible to prescribe or dispense NVPs felt that the current regulatory model placed an undue time and responsibility burden on clinicians.

CONCLUSION

Our research identified several limitations associated with the current Australian prescription-only regulatory model. These were perceived by healthcare professionals to limit the potential for the regulations to reduce youth use and to increase access to safer NVP products for people who smoke to use for smoking cessation.